Anti-Caking Agents Dont Protect Vitamin C

WEST LAFAYETTE, Ind.Anti-caking agents meant to protect vitamin C from moisture in powdered food products may instead hasten degradation of the nutrient, according to a study from Purdue University.

In an effort to understand how anti-caking agents protect substances, such as vitamin C,  from humidity, the researchers blended a variety of anti-caking agents with powdered sodium ascorbate and exposed the blend to different relative humidity levels. Results showed that some of the anti-caking agents caused vitamin C to dissolve at lower humidity levels than normal. Typically, sodium ascorbate dissolves at 86 percent relative humidity and is stable below that level. Some anti-caking agents, however, caused the degradation to begin at lower humidity levels.

"Some of the agents act like little raincoats, covering the particles and protecting them from moisture. Others will absorb the water themselves, keeping it away from the vitamin C particles," said Lisa Mauer, a professor of food science. "I really thought some of those anti-caking agents would help, but they didn't."

According to a Purdue press release, the problem is the chemical properties of the anti-caking agents themselves. The water-repellent agents are mobile, according to the researchers, and when they move around they clump together and leave some of the vitamin C uncovered. When that happens, moisture is able to reach and degrade the exposed vitamin C.

The moisture-absorbing agents, which absorb the water at a lower humidity than vitamin C, may be absorbing so much moisture that they become saturated. When that occurs, the pH level around the vitamin C can change, or water can move and interact with the vitamin C.